 Lake Baikal is home to a large number of gas hydrates which contain methane and ethane. These hydrates have been found to be composed of two distinct types, structure I and structure II. Structure I hydrates are composed of methane only, while structure II hydrates contain both methane and ethane. The composition of these hydrates is influenced by the isotopic signature of the lake water, which is characterized by low hydrogen isotope ratios. This leads to the production of ethane with a much lower hydrogen isotope ratio than expected, suggesting that this lake water may play a role in the formation of microbial ethane. Additionally, the presence of ethane in the hydrates indicates that the gas is being biodegraded, leading to a unique system of mixed methane ethane gases. This article was authored by Akihiro Hachikubo, Hirotsu Duminomi, Hirotoshi Sakagami, and others.